O.J. Simpson? No way. No one saw that coming. Almost anyone in Buffalo, in fact, who spent five minutes in close proximity to the Juice out in the world was immediately eager to report to the world that he was virtually the ideal celebrity – affable, patient, just about as good to his fans under all circumstances as a superstar athlete could possibly be.

No one could have seen Robert Blake coming either. In fact, he spent more than a decade as one of the favorite interviews of America’s entertainment writers – the self-styled “Ragtime Billy Peaches” of TV hype. He was his era’s more subdued and less addled version of Charlie Sheen at his most quotable.

But Phil Spector, whose fall is the subject of an HBO film premiering tonight, was another matter altogether. To “know, know, know him” was not necessarily to “love, love, love him”, no matter what his 1958 record with the Teddy Bears said.

Spector was legendary for being an all-American “weirdo,” a reclusive pop music genius whose oddness was known to all the minute Tom Wolfe got hold of him in his essay “First Tycoon of Teen.” His penchant for collecting and brandishing guns had long since made it out of music’s underground. (Spector’s onetime arranger and right-hand man, the late Jack Nitzsche, was accused by actress Carrie Snodgress of raping her with a gun. In a notable departure from coastal big shots getting away with it completely, Nitzsche was forced to plead guilty to a lesser charge in 1979 and was put on three years’ probation.)

Spector’s ex-wife Ronnie Spector was never shy about telling the world about Spector’s oddities and cruelties as a husband. You could even look at Spector’s gigantic output as one of the greatest record producers of all time and find some headshakers that would give anyone pause – the Crystals’ song “He Hit Me (And It Felt Like a Kiss),” for instance which was, yes, written by Gerry Goffin and Carole King (who would later write Little Eva’s “Please Hurt Me”).

You could say, then, that the world was just waiting for Phil Spector’s life to go Gothic on us – praying for it even. And it finally happened on the evening of Feb. 3, 2003, when actress Lana Clarkson – whom he’d picked up at a club – was found dead of a gunshot to the head in Spector’s fabled weird “castle.”

His driver had told police that night Spector had said afterward “I think I just killed someone.”

The case was tabloid bliss – a beautiful, sexy but overage (40) “actress slash model slash whatever” found dead in the company of the man long known in America as one of the strangest and most reclusive pop geniuses of all.

And he was all of that from the time he came up through the ranks of Brill Building titans Jerry Leiber and Mike Stoller. Spector’s “Wall of Sound” on his elaborately produced 45 rpm beauties made for some of the most remarkable hits of his or any other time.

His touch was golden. His own groups had names like the Crystals, the Ronettes and Bob B. Soxx and the Blue Jeans, but in his prime everyone wanted a piece of Spector, the record producer – the Drifters, John Lennon, the Righteous Brothers, Ike and Tina Turner.

The Righteous Brothers’ “You’ve Lost That Lovin’ Feeling” was a nasty piece of American recording studio baroque. You could launch oratorios with its musical forces – strings, voices, everyone you could fit into a recording studio and an overdub. Ike and Tina Turner’s “River Deep and Mountain High” was insane Spector Rococo – too much, ultimately, even for America’s hype and hit machine. It was only in subsequent years that we’ve come to love all that insanity enveloping Tina Turner and her rag doll reminiscences.

And none of it helped Lana Clarkson one bit. She was still very dead at 40 in the house of a peculiar man who’d long been trailed by tales of drugs and abuse and a house full of guns he liked to brandish.

And now on HBO this evening at 9, we have the Spector legal team joined by writer/director David Mamet (in his most original and best effort since his script for “Wag the Dog”), Al Pacino and Helen Mirren. You’re unlikely to see a better case for innocence.

It’s a “work of fiction not based on a true story” the film hastens to assure us before it even begins – a disclaimer that sets the 2013 record, thus far, for disingenuousness even for Hollywood, where disingenuousness is practically imbibed with every bottle of designer water.

Forget the Crystals, Ronettes, Bob B. Soxx and the Blue Jeans and Ike and Tina, “Phil Spector” is solely about his trial for the murder of Lana Clarkson. Did he put a gun in her mouth and pull the trigger? Or did she do it herself in a decidedly spectacular and malevolent act of suicide?

Pacino is brilliant as the shrimpy Spector, shambling around his castle in a large variety of silk scarves and bizarre wigs and launching wild and woolly (and frequently hilarious) self-defense monologues at Mirren, playing his lawyer Linda Kenney Baden, who remained faithful after his first chief attorney Bruce Cutler quit over differences with, uhhh, his client. Jeffrey Tambor, the great comic actor (“Arrested Development”) has the best serious role he’s had in years playing it sour and logical and self-protective as Cutler, a man who knew how eager a California jury was to finally convict a famous man for being too weird for comfort (even though the crime he was officially tried for was murder, the same crime that O.J. and Robert Blake were acquitted of).

And that, as Mamet tells the tale, is pretty much what happened. But what we get is the sight of the great Mirren, as Baden, sucked reluctantly into Spector’s defense despite suffering pneumonia during his first trial. And Pacino, playing his newest real-world gargoyle for HBO (Dr. Kevorkian aka “Dr. Death” was the first), giving us those marvelously cynical Mamet monologues of self-defense that make this thing one of the most vigorous defenses of celebrity weirdness since Bob Fosse’s “Lenny” starred Dustin Hoffman in Fosse and writer Julian Barry’s version of martyred comedian Lenny Bruce (one of Spector’s idols, of course).

As Mamet’s film gives us Spector, guns were the only way Spector could keep women from fleeing his company. That’s why so many of them came out of the woodwork with tales of Spector and guns after Clarkson died.

But the insurmountable forensic problem, as Mamet sees it – besides the infinite human capacity for charging eccentrics exorbitantly for fame and weirdness – is that the white jacket Spector was wearing at the time of her death should have been covered with blood and brain tissue if he’d been the one to put a gun in Clarkson’s mouth and pulled the trigger.

Well, it wasn’t. There were, in fact, only a couple barely visible drops of blood spatter, according to Mamet (and, as well, Spector’s young wife Rachelle in her current publicity interviews).

It’s hard to argue with that.

Mamet’s shamblingly eloquent Spector also argues that the reason his driver quoted him admitting he may have shot someone is that the driver’s English was so poor he may have misunderstood him completely. It’s hard for us to argue with that too.

It occurred to me watching all this – which succeeds enormously by sheer virtue of the terrific interplay between Pacino as Spector and Mirren as his most reluctant attorney – that there is a possibility which could well explain everything: Spector’s whistle-clean white jacket and the dazed and addled confession of guilt his driver heard right afterward.

To wit: what if Spector, in a moment of viciously sadistic and decadent play, goaded his suicidal female visitor into putting the gun in her mouth, either for perverse erotic reasons or emotionally despairing ones? And then either talked her into pulling the trigger – or watched in horrified surprise as she actually did, either deliberately or by accident, what she’d threatened to do? He’d have been far enough away that his white jacket would be largely unbesmirched. He might also have been suddenly shocked and even remorseful enough to mutter guiltily to his staff.

But that, as HBO’s disclaimer might say, is pure fiction that I invented out of whole cloth entirely because it’s a possibility that explains all the discordant facts.

What actually happened was this: after being abandoned by Cutler, Baden’s summation was good enough to help get pop music’s oddest eccentric a hung jury at his first trial (the vote was 10 to 2 in favor of guilt). On his second trial with yet another legal team (Baden said she was too ill to participate), he was convicted of second-degree murder.

He was sentenced to 19 years to life. He’s 73 now and serving his sentence at the state’s Prison and Drug Treatment Facility in Corcoran, Calif. He won’t be eligible for parole until he’s 88.